JSON is just a general data structure specification whereas Newick is specifically used for trees. I don't think there are any standardize rules for representing Newick in JSON. You'll have to tailor something according to how you want to use the JSON data. Why do you want to convert it to JSON?

What's great about using python to output JSON is that stringifying native python arrays/dictionary conforms to JSON specs. So you can really just print str(myStructure) and it will output JSON accordingly.

Like I said previously, I am not sure how you want the JSON to look as there are no standardized rules for writing Newick in JSON. I just made it output a simple key:value structure. For example the output of your sample would be something like: (I took out a bunch of data in the middle so I don't go over the post character limit)

I adapted this functions to fit the newick-format regarding the optional branch-lengths. Now I've got three keys for each node/leaf: a "label", a "distance" and a "tree" ("tree" contains the nested clades). Code available here: http://pastebin.com/Pk717Uc2